Content mastered for ultra-high definition television (UHDTV) is becoming widely available with the introduction of high dynamic range (HDR) systems. These systems provide an immersive experience with more life-like reproduction of video content. A typical HDR system is characterized by:                high peak luminance (e.g., at least 700, 1000, 2000, or 10000 cd/m2);        HDR electro-optical transfer function (EOTF) (e.g., SMPTE ST 2084:2014, “High Dynamic Range Electro-Optical Transfer Function of Mastering Reference Displays;” or Hybrid Log-Gamma, ITU-R Recommendation BT.2100-0 (July 2016), as well as BBC Research & Development White Paper WHP 283, July 2014, “Non-linear Opto-Electrical Transfer Functions for High Dynamic Range Television”);        wide color gamut (e.g. DCI-P3, ITU-R Recommendation BT. Rec. 2020, or greater);        increased contrast ratio (e.g., at least 800:1, 5000:1, or 10000:1); and        4K pixel resolution or greater (e.g., 3840×2160 pixels, 4096×2160 pixels, 7680×4320 pixels, or the like).        
Predictably, disparate UHDTV content formats will emerge. For example, UHDTV formats can rely on different CVT models based on parametric tone mapping metadata, content-dependent dynamic metadata, and/or reference display metadata, or even no metadata at all. Ideally, irrespective of HDR content format, an HDR system should maintain artistic intent—color and brightest, to at least a reasonable extent. Reasonable rendering is assured by archiving content mastered in each of the HDR formats to be supported. However, this simplistic solution requires larger memory storage, longer content creation time, and increased complexity in content delivery.
The inventors appreciate that transitioning from one HDR format in a computationally efficient manner is preferable. An HDR device should accurately render content mastered in another format (such as, one based on a distinctly different CVT model), or at least render a perceptually reasonable approximation, based on available metadata.